Titania nanoparticles with two crystalline structures (anatase-rutile) and coated titania with different amount of tin dioxide (A-R-S#1 and A-R-S#2) are prepared through hydrolysis method. X-ray diffraction analysis (XRD) confirmed the presence of both anatase and rutile structures in the synthesized titania nanoparticles. In addition, the characteristic peak of tin dioxide in A-R-S#2 was higher than that of A-R-S#1. The photocatalytic activity of the prepared photocatalysts was evaluated using a vapor mercury lamp (150 W) for decomposition of methylene blue. The results of the photocatalytic activity variation showed that the photocatalytic activity of all the synthesized photocatalysts increases by increasing the UV irradiation time (in the range of 5 min to 20 min) and weight fraction of photocatalysts (pH = 4, pH = 8, pH = 12). The pH of suspension had negative effect on photocatalytic activity. The least and most photocatalytic activity belonged to the synthesized anatase-rutile titania and A-R-S#2, respectively. Increasing the amount of tin dioxide nanoparticles on the surface of titania leads to the enhancement of photocatalytic activity. The results of the analysis of variance showed that all the main factors and their binary and triple interactions significantly affect photocatalytic activity.